Four boys, including two aged 14, killed another teenager on the streets of London in an "unprovoked" and "senseless" knife attack, a court heard.
The group allegedly took a minicab from an estate in Hendon to Harrow, west London, then asked the driver to wait as they murdered 19-year-old Hussein Ahmed and attacked two 17-year-olds, the court heard.
After seven or eight minutes, they returned to the cab and told the driver "Drive, boss", the court heard
Mr Ahmed was stabbed once in the back in a street near the South Harrow tube and suffered massive blood loss. He died in hospital three days later.
Another boy was stabbed in the arm and stomach while a third narrowly avoided injury as an attacker slashed the sleeve of his jacket.
Two 14-year-olds and a 16-year-old, who was 15 at the time, are on trial at the Old Bailey, accused of murder, wounding with intent and attempted wounding with intent.
They are also charged with conspiracy to cause grievous bodily harm.
The boys, who cannot be named because of their ages, deny the charges.
A fourth alleged attacker aged 16 fled the country and is wanted by police, the court heard.
Prosecutor Anthony Orchard QC told jurors: "Sadly, this case is about the death of another young man who lost his life to a senseless stabbing which took place on a street in London.
"On Friday November 18 last year, shortly after 5pm, Hussein Ahmed was stabbed once in the back. The attack was unprovoked.
"Hussein Ahmed was treated close to the scene of the stabbing. Passers-by, police and paramedics tried to stem the blood loss. Sadly, he died three days later."
Mr Orchard told jurors they would be shown CCTV footage and hear from eyewitnesses as well as an analysis of the defendants' mobile phones.
On the afternoon of the attack, the alleged attackers' phones located them at the Grahame Park Estate in Hendon.
At 4.13pm, the mobile phone of one of the defendants was used to call for a cab, jurors were told.
The caller was quoted £18 by Embassy Cars for the return journey from the Grahame Park Estate to Station Road in Harrow.